Complete repair guide for the Winnebago Minnie Winnie – Furnace Igniter & Control Board Replacement. Follow these steps to diagnose and fix the issue yourself.
Parts & Tools You’ll Need
- Suburban RP-35Q 35,000 BTU/h RV Replacement Core for Suburban Furnace Series SF-35, SF-35Q, SF-42, SF-42Q, and SF-Q (2609A) — Suburban/Atwood RV furnace (replacement unit)
- Fit For Suburban RV Furnace Parts 232286,Single Probe Gas Furnace Igniters Electrode with Wire Assembly, Camper Furnace For Suburban 232286 Above 934701426 SF-20, SF-25, SF-30, SF-35 (SF Series) — Furnace igniter electrode
- DTAIR 33082 Sail Switch Replacement for Select Dometic Atwood RV Furnace(Pack of 2) — Furnace sail switch
- 520814 Rv Water Heater Module Board Ignition Control Circuit Board Compatible with Suburban Furnace SW4D, SW6D, SW6DE, SW12D, SW6DEM RV Water Heaters,Replace 520814 520820 520871 33550L (With lid) — Furnace circuit board / control board
- DTAIR 33082 Sail Switch Replacement for Select Dometic Atwood RV Furnace(Pack of 2) — Furnace high-limit switch
- Suburban 232684 RV Furnace 12v SF-Series DC Blower Motor, SF-35, SF-35F, SVF-35, SF-42, SF-42F OEM Caliber — Furnace blower motor (12V DC)
- RV Carbon Monoxide & Propane Gas Alarm, Briidea Dual LP/CO Detector with Separate LED Indicator Light, 100dB Loud Alarm, 12 VDC, Black — Propane/CO combo detector alarm
- FKM Pro Digital Multimeter Tester TRMS 6000 Counts,Smart Rechargeable Voltmeter 5″Color LCD,Auto-Ranging Automotive Multimeters,for AC/DC Current/Voltage,NCV,Ohm,Capacitance,Resistance,Continuity,Temp — Digital multimeter
Step 1: Diagnose Furnace Failure and Prepare Work Area
Begin by locating your Winnebago Minnie Winnie’s furnace, typically positioned in the basement compartment near the water heater. Turn off the propane supply at the tank valve and disconnect the 12V DC power from your battery disconnect switch or fuse panel to ensure complete power isolation. Use your digital multimeter set to the 12V DC setting to verify that all power has been safely disconnected before proceeding—you should read 0V across the furnace control board terminals.
Step 2: Remove Furnace Access Panels and Components
Open the furnace access panel by removing 4-6 fasteners (typically Phillips head screws) that secure the front cover. Carefully disconnect the electrical harness connectors leading to the furnace blower motor and control board, taking a photo or labeling each connector to ensure proper reassembly. Document the exact positions of all wiring before removal, as the Atwood/Suburban furnace systems use color-coded harnesses that must be reconnected in their original positions.
Step 3: Disconnect Propane Line and Mounting Hardware
Locate the propane inlet line connected to the furnace—typically a 3/8-inch compression fitting at the bottom rear of the unit. Using a wrench set, hold the fitting body steady with one wrench while turning the compression nut counterclockwise with another to prevent damage to the line. Remove all furnace mounting bolts (usually 4 bolts, 1/2-inch) that secure the unit to the frame, then carefully slide the furnace assembly out toward you.
Step 4: Replace Igniter Electrode and Control Board Assembly
On your old furnace, locate the igniter electrode—a ceramic-tipped component protruding into the burner chamber, typically held by a single mounting screw. Unscrew and remove this electrode, then install the new furnace igniter electrode in the identical position, ensuring the ceramic tip sits 1/4-inch to 3/8-inch from the burner orifice. Next, disconnect the two wire terminals from the old furnace circuit board and transfer them to the new control board, matching the terminal designations (typically labeled as Igniter and Gas Valve).
Step 5: Verify Sail Switch and High-Limit Switch Function
Inspect both the furnace sail switch (a small flapper that detects airflow) and the high-limit switch (a thermal safety device) on your replacement unit to confirm they move freely without obstruction. Test the sail switch by gently pushing the flapper with your finger—it should move smoothly and return to its resting position. Check that the high-limit switch wires are securely seated in their terminals, as a loose connection here will prevent furnace operation and trigger safety shutdowns.
Step 6: Reinstall Furnace and Reconnect All Systems
Carefully position your new furnace assembly back into the RV basement compartment and align the mounting bolt holes with the frame. Secure the furnace using all four 1/2-inch mounting bolts, tightening in a cross-pattern (top-left, bottom-right, top-right, bottom-left) to 25-30 foot-pounds to ensure even pressure and prevent warping. Reconnect the propane inlet line by hand-threading the compression nut first, then tightening firmly with a wrench—do not overtighten, as this can damage the fitting (final torque should be approximately 12-15 foot-pounds).
Step 7: Test Furnace Operation and Verify System Safety
Restore 12V DC power to your furnace by reconnecting the battery disconnect switch, then turn the propane supply valve back on at the tank. Set your RV thermostat to heat mode and a temperature 5 degrees above the current interior temperature, then listen for the blower motor to activate within 30 seconds—you should hear a click from the gas valve solenoid followed by the igniter electrode sparking (a faint clicking sound at 3-4 Hz). Finally, verify that your Propane/CO combo detector alarm shows no warnings, allow the furnace to run for 10 minutes and confirm that warm air flows consistently from all heating vents without any smell of unburned propane.